Nitride micro light emitting diode with high brightness and method of manufacturing the same

ABSTRACT

The present invention relates to a nitride micro light emitting diode (LED) with high brightness and a method of manufacturing the same. The present invention provides a nitride micro LED with high brightness and a method of manufacturing the same, wherein a plurality of micro-sized luminous pillars  10  are formed in a substrates, a gap filling material such as SiO 2 , Si 3 N 4 , DBR(ZrO 2 /SiO 2  HfO 2 /SiO 2 ), polyamide or the like is filled in gaps between the micro-sized luminous pillars, a top surface  11  of the luminous pillar array and the gap filling material is planarized through a CMP processing, and then a transparent electrode  6  having a large area is formed thereon, so that all the luminous pillars can be driven at the same time. In addition, the present invention provides a nitride micro LED with high brightness in which uniformity in formation of electrodes on the micro-sized luminous pillars array is enhanced by employing a flip-chip structure.

FIELD OF THE INVENTION

The present invention relates to a nitride micro light emitting diode(LED) with high brightness and a method of manufacturing the same, andspecifically to a nitride micro light emitting diode (LED) with highbrightness and a method of manufacturing the same, in which luminousefficiency is maximized by finely adjusting micro-sized nitride luminouselements and allowing an array of the elements to be driven at the sametime.

BACKGROUND OF THE INVENTION

In recent, because of excellent characteristics of a gallium nitride(GaN) semiconductor, a nitride semiconductor LED is widely studied.

Specifically, in order to use the nitride LED for illumination as wellas for display, the brightness limit of the commercialized LED should beovercome.

The nitride LED generally emits light in an element area having adiameter of 300 μm or more. The light emitted from a luminous layer maynot get out of the element and be locked in the element, so that thenitride LED has a limit that its external luminous efficiency does notexceed 30%.

In order to solve this problem, the internal luminous efficiency and theexternal luminous efficiency should be optimized, respectively. Sincemost GaN is grown using a heterogeneous epitaxy technology, a pluralityof lattice defects necessarily exist therein, thereby resulting indeterioration of the internal luminous efficiency.

Nonetheless, the recent GaN growth technologies have a tendency to bebased on the heterogeneous epitaxy technology, and thus it is difficultto expect enhancement of the internal luminous efficiency any more.Therefore, trials for enhancing the luminous efficiency throughtechnologies such as efficient formation of electrodes and packagingtechnologies of enhancing concentration of light with an elementstructure previously optimized and grown into a thin film have beenissued.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

FIG. 1 is a view illustrating a micro light emitting diode (LED)according to one embodiment of the present invention;

FIGS. 2A to 2E are views illustrating a method of manufacturing themicro LED shown in FIG. 1;

FIGS. 3 and 4 are views illustrating modifications of the micro LEDaccording to one embodiment of the present invention;

FIG. 5 is a view illustrating another modification of the micro LEDaccording to one embodiment of the present invention; and

FIGS. 6A to 6D are views illustrating a method of manufacturing themicro LED using a selective re-growth method in place of a dry etchingmethod in manufacturing the micro LED shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Technical Theme

In order to solve the above problems, the present invention is contrivedto provided a nitride micro LED with high brightness improved using anitride semiconductor having a previously-optimized andgrown-into-thin-film structure. Therefore, it is an object of thepresent invention to provide a nitride micro LED with high brightnessand a method of manufacturing the same, in which a luminous area isincreased as large as possible to allow light emitted from an activelayer to get out of an element, by controlling luminous elements in amicro size.

It is another object of the present invention to provide a nitride microLED with high brightness which consumes the same power as theconventional large-area LED and of which the luminous efficiency is moreexcellent, and a method for manufacturing the same.

Technical Solution

In order to accomplish the above objects, according to one preferredembodiment of the present invention, a nitride micro LED with highbrightness consuming the same power as the conventional large area LEDbut having more excellent luminous efficiency, and a method ofmanufacturing the same.

In order to accomplish the aforementioned objects, the present inventionprovides a nitride micro LED (Light Emitting Diode) with high brightnesshaving a plurality of luminous pillars, the LED comprising: a pluralityof micro-sized luminous pillars having an n-type GaN layer formed on asubstrate, an active layer formed on the n-type GaN layer, and a p-typeGaN layer formed on the active layer; a gap filling material filledbetween the luminous pillars to have substantially the same height asthe luminous pillars; a p-type transparent electrode formed on a topsurface of the gap filling material and the luminous pillars; a p-typeelectrode formed on the p-type transparent electrode; and an n-typeelectrode electrically connected to the n-type GaN layer, wherein anarray of the luminous pillars is driven at the same time.

In the present invention, it is preferable that the gap filling materialincludes at least one selected from SiO₂, Si₃N₄ or a combinationthereof, polyamide, and ZrO₂/SiO₂ or HfO₂/SiO₂.

In the present invention, the gap filling material is formed to havesubstantially the same height as the luminous pillars through a CMP(Chemical Mechanical Polishing) process.

In the present invention, a top surface of the p-type GaN layer of theluminous pillars may have convex surfaces formed through the CMPprocess. In this case, the convex surfaces serve as lenses.

In the present invention, it is preferable that the transparentelectrode comprises a combination of oxidized Ni/Au(NiO/Au) or an ITO(Indium Tin Oxide).

In the present invention, it is preferable that the nitride micro LEDfurther comprises a pair of DBR (Distributed Bragg Reflectors) layersformed on a top surface of the transparent electrode and a bottomsurface of the substrate, respectively.

In the present invention, the nitride micro LED may further comprise anAR (Anti-reflection) layer coated on a top surface of the transparentelectrode or a bottom surface of the substrate.

In the present invention, the luminous pillars may have side surfacesformed obliquely. In this case, it is preferable that the nitride microLED further comprises a DBR layer made of ZrO₂/SiO₂ or HfO₂/SiO₂ andformed below the gap filling material within gaps between the luminouspillars.

Furthermore, the present invention provides a nitride micro LED withhigh brightness which is mounted through a flip-chip method, the nitridemicro LED comprising: a sapphire substrate; a plurality of micro-sizedluminous pillars having an n-type GaN layer grown on the sapphiresubstrate, an active layer formed on the n-type GaN layer and a p-typeGaN layer formed on the active layer; a gap filling material filledbetween the luminous pillars to have substantially the same height asthe luminous pillars; a metal electrode formed on a top surface of thegap filling material and the luminous pillars; a p-type electrode formedon the metal electrode; and an n-type electrode electrically connectedto the n-type GaN layer, wherein an array of the luminous pillars isdriven at the same time.

Furthermore, the present invention provides a method of manufacturing anitride micro LED with high brightness having a plurality of microluminous pillars, the method comprising: (a) a step of sequentiallygrowing an n-type GaN layer, an active layer, and a p-type GaN layer ona wafer or substrate; (b) a step of dry-etching the processed wafer toform the luminous pillars having the n-type GaN layer, the active layerand the p-type GaN layer on the substrate; (c) a step of depositing agap filling material in gaps between the luminous pillars; (d) a step ofplanarizing a top surface of an array of luminous pillars and a topsurface of the gap filling material using a CMP process; and (e) a stepof depositing a transparent electrode on all of the top surfaces of thearray of luminous pillars and the gap filling material, depositing ap-type electrode and an n-type electrode at predetermined positions,respectively, and heating the resultant structure.

In the present invention, it is preferable that the step (c) is carriedout such that the gaps between the luminous pillars are completelyfilled with the gap filling material, and the step (d) is carried outsuch that the top surface of the luminous pillars and the top surface ofthe gap filling material have the same height as each other.

In the present invention, the step (c) may be carried out such that thegaps between the luminous pillars are completely filled with the gapfilling material, and the step (d) may be carried out such that the topsurface of the p-type GaN layer in the luminous pillars is formed tohave convex surfaces.

In the present invention, it is preferable that the gap filling materialincludes at least one selected from SiO₂, Si₃N₄ or a combinationthereof, polyamide, and ZrO₂/SiO₂ or HfO₂/SiO₂.

In the present invention, it is preferable that the transparentelectrode comprises a combination of oxidized Ni/Au(NiO/Au) or an ITO(Indium Tin Oxide).

In the present invention, it is preferable that the method furthercomprises, after the step (e), a step of depositing a pair of DBR(Distributed Bragg Reflectors) layers on a top surface of thetransparent electrode and a bottom surface of the substrate.

In the present invention, it is preferable that the method furthercomprises, after the step (e), a step of coating an AR (Anti-reflection)layer on a top surface of the transparent electrode or a bottom surfaceof the substrate.

In the present invention, in the step (b), process variables may becontrolled such that side surfaces of the luminous pillars are formedinto oblique portions. In this case, it is preferable that the methodfurther comprises, between the step (b) and the step (c), a step ofdepositing a DBR layer within the gaps between the luminous pillars.

Furthermore, the present invention provides a method of manufacturing anitride micro LED with high brightness having a plurality of microluminous pillars, the method comprising: (a) a step of sequentiallygrowing an n-type GaN layer, an active layer and a p-type GaN layer on asapphire wafer or substrate; (b) a step of dry-etching the processedwafer to form the luminous pillars having the n-type GaN layer, theactive layer and the p-type GaN layer on the substrate; (c) a step ofdepositing a gap filling material in gaps between the luminous pillars;(d) a step of planarizing a top surface of an array of luminous pillarsand a top surface of the gap filling material using a CMP process; and(e) a step of depositing a metal electrode on the overall top surface ofthe array of luminous pillars, depositing a p-type electrode and ann-type electrode thereon, respectively, and heating the resultantstructure.

Furthermore, the present invention provides a method of manufacturing anitride micro LED with high brightness having a plurality of microluminous pillars, the method comprising: (a) a step of growing an n-typeGaN buffer layer on a wafer or substrate; (b) a step of depositing anoxide film on the n-type GaN buffer layer; (c) a step of wet-etching andpatterning the oxide film such that the oxide film has the plurality ofpillars and gaps therebetween; (d) a step of sequentially re-growing ann-type GaN layer, an active layer and a p-type GaN layer up to a heightof the oxide film pillars using the n-type GaN buffer layer exposed in abottom surface of the gaps; and (e) a step of depositing a transparentelectrode on the overall top surface of the array of luminous pillarsre-grown, depositing a p-type electrode at a predetermined position,depositing an n-type electrode on the n-type GaN layer, and heating theresultant structure.

In the present invention, it is preferable that the method furthercomprises, after the step (e), a step of depositing a pair of DBR(Distributed Bragg Reflectors) layers on a top surface of thetransparent electrode and a bottom surface of the substrate.

In the present invention, the method may further comprises, after thestep (e), a step of coating an AR (Anti-reflection) layer on a topsurface of the transparent electrode or a bottom surface of thesubstrate.

Peculiar Effect

According to the present invention as described above, by filling gapsbetween the luminous pillars in the nitride micro luminous pillar arraywith the gap filling material, planarizing the resultant structure usingthe CMP process, and forming the transparent electrode on the surfacethereof, it is possible to maximize the luminous area and thus toexternally use the light emitted from the active layer with a highefficiency.

In addition, it is possible to provide the nitride micro LED with highbrightness, which consumes the same power as the conventional large-areaLED and of which the luminous efficiency is more excellent.

Further, according to the present invention, by using the nitride microLED with high brightness having an improved structure, it is expected topromote demands of LEDs for display and illumination. Furthermore, thepresent invention can apply to a method of manufacturing a micro LED formicro display.

Although the present invention has been described in connection with thepreferred embodiments with reference to the accompanying drawings, thepreferred embodiments are intended not to limit the invention but toexemplify best modes of the present invention. It will be understood bythose skilled in the art that various changes or modifications may bemade thereto without departing from the spirit and scope of theinvention. Therefore, the present invention is defined only by theappended claims which should be construed as covering such changes ormodifications.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, preferred embodiments of the present invention will be described indetail with reference to the appended drawings.

First Embodiment

FIG. 1 is a view illustrating a micro LED according to one embodiment ofthe present invention, and FIGS. 2A to 2E are views illustrating amethod of manufacturing the micro LED shown in FIG. 1.

As shown in FIG. 1, a nitride micro LED with high brightness accordingto the present invention comprises a substrate 1, a n-type GaN layer 2,an active layer 3, a p-type GaN layer 4, a gap filling material 5, atransparent electrode 6, a p-type electrode 7, an n-type electrode, anda DBR (Distributed Bragg Reflectors) layer 9. The reference numeral 10in FIG. 1 denotes micro-sized luminous pillars.

Specifically, the n-type GaN layer 2, the InGaN/GaN active layer 3, thep-type GaN layer 4 sequentially grown and disposed on the sapphire(Al₂O₃) substrate 1 grown in a predetermined direction constitutes aplurality of micro-sized luminous pillars or luminous element pillars10.

The luminous element pillars 10 are formed to be a circular cylindershape in order to maximize the area for emitting light. Of course, theluminous element pillars 10 of the present invention may be formed to bea polygonal pillar shape other than the circular cylinder shape.Further, the diameter of the luminous element pillars 10 can be adjustedfrom 0.5 μm close to the wavelength of emitted light to several tens μm.Furthermore, the height of the pillars 10 can be adjusted such that theactive layer, the n-type doped layer and the p-type doped layer all areincluded in the pillars. Such elements are formed using a dry etchingmethod or a selective re-growth method. In this embodiment, amanufacturing method using the dry etching method will be firstdescribed, and then a manufacturing method using the selective re-growthmethod will be described in detail in an embodiment with reference toFIGS. 6A to 6D.

The gap filling material 5 is a material for filling in the gaps formedbetween the luminous element pillars 10, and facilitates the formationof electrodes of the respective pillars 10 through the planarizationprocess. Materials usable for the gap filling material include SiO₂,Si₃N₄, a combination of SiO₂ and Si₃N₄, polyamide, ZrO₂/SiO₂, HfO₂/SiO₂and so on. The method such as plasma enhanced chemical vapor deposition(PECVD), evaporation and sputtering is used for depositing the gapfilling material.

A combination of oxidized Ni/Au(NiO/Au) or ITO (Indium Tin Oxide) isused for the transparent electrode 6. The transparent electrode 6 isformed on a surface of the upper p-type GaN layer 4 of the luminouselement pillars 10 and a top surface 11 of the gap filling material 5 todrive all the pillars 10 at the same time with the electrical pumping ofthe respective luminous element pillars 10. Here, the surface of theupper p-type GaN layer 4 of the luminous element pillars 10 and the topsurface 11 of the gap filling material 5 should be planarized through apredetermined process in advance.

The p-type electrode 7 and the n-type electrode 8 are made of at leastone conductive material selected from gold (Au), aluminum (Al), copper(Cu) or alloys thereof.

The DBR layer 9 is formed on the transparent electrode 6 and a backsurface of the substrate 1 as a layer having a high reflectivity forformation of the micro LED having a resonant cavity.

Like above, the micro-sized nitride luminous element of the presentinvention basically comprises the micro-sized luminous pillars, the gapfilling material to be filled in the gaps between the pillars, DBRlayers for formation of the resonant cavity LED (RCLED), and electrodesfor the electrical pumping.

In other words, a point most different from the commercializedlarge-area LED is that the area for emitting light is enhanced by meansof an array of micro-sized luminous elements in place of the large areaas a plane. Further, in order to allow the luminous element array to bedriven at the same time, a material such as silica is filled between thepillars, a structure having the transparent electrode is efficientlyformed through a planarization process.

More specifically, a method of manufacturing the nitride micro LED willbe described with reference to FIGS. 2A to 2E.

First, as shown in FIG. 2A, a luminous layer excellent in an internalluminous efficiency is grown using a metal organic chemical vapordeposition (MOCVD) method. That is, the n-type GaN layer 2 is formed ona sapphire wafer or substrate 1 having a predetermined crystaldirection, the InGaN/GaN quantum well (QW) active layer 3 is formedthereon, and then the p-type GaN layer 4 is formed thereon.

Next, the wafer on which the semiconductor luminous element structure isformed like above is dry-etched into pillar shapes as shown in FIG. 2B.This etching is carried out by means of an ICP (Inductive CoupledPlasma) process using a reactive gas such as Cl₂, BCl₂ or the like. As ashape of the luminous pillars 10, a polygonal shape may be selected inaddition to a circular shape expected to be excellent in the luminousefficiency.

At that time, the height of the luminous pillars 10 is about 1 μm moreor less such that the QW structure, the n-type GaN layer and the p-typeGaN layer are all included in the pillars, and the diameter of theluminous pillars 10 is about 0.4 μm to several tens μm for formingphotonic crystals.

After the etching process, the gap filling material 5 is deposited inthe gaps 12 between the luminous pillars 10. At that time, the fillingmaterial 5 is generally deposited in the same shape as shown in FIG. 2C.Therefore, the first deposition thickness of the gap filling material 5should be at least the height of the luminous pillars 10 or more, and anaccurate process selection and an accurate process control are requirednot to finally form voids in the gap filling layer due to deposition ofthe gap filling material. In order to satisfy such requirements, it ispreferable that the process of depositing the gap filling material 5employs a high-density plasma enhanced deposition method. In addition,as the gap filling material 5, SiO₂, Si₃N₄, a combination of SiO₂ andSi₃N₄, polyamide, ZrO₂/SiO₂, HfO₂/SiO₂ and so on can be used.

The raw materials of the gap filling material 5 can surely provideinsulation between the respective luminous pillars 10 and can bethermally stable for the heat treatment in later processes, and inaddition the refraction index thereof is higher than that of air todecrease a fresnel loss of the emitted light. Specifically, when ZrO₂ orHfO₂/is used for the first layer on side surfaces of the GaN layer,compared with a case of using only SiO2, difference in refraction indexfrom the GaN is further decreased, thereby further decreasing the totalreflection and the fresnel loss.

As shown in FIG. 2D, the deposited gap filling material 5 is subjectedto a planarization process for providing the uniform transparentelectrode all over the top surface of the array of luminous pillars 10.Although the planarization process can include various methods, the CMPprocess is suggested as a most effective method in the presentinvention.

Specifically, in order to make the heights of the luminous pillars 10and the deposited gap filling material 5 equal to each other, theplanarization process is carried out in the present invention. Theplanarization process is carried out by depositing a thick photo resist(PR) film, and performing a dry etching method in which the oxide filmand the PR film are etched at the same speed or the CMP (ChemicalMechanical Polishing) method. Specifically when the CMP is used, sinceonly the oxide film can be selectively etched and the GaN film can beused as a stopper layer of planarization, the controllability and thereproducibility are excellent.

In other words, since GaN is very stable chemically and mechanically,the CMP method of removing the gap filling layer 5 deposited on the topsurface of the luminous pillars 10 does not damage the GaN layer. Thatis, since the array of luminous pillars 10 themselves can be used as theend point layer of planarization, the reproducibility and thereliability of the planarization process can be considerably enhanced.

As a solution used for the CMP process, a general alkaline solution ofsoftening the oxide film is used. A commercialized product of thealkaline solution can be include Syton, in which the softness of oxidefilm can be controlled by adjusting the acidity (pH) of the alkalinesolution. Fine SiO2 or Al2O3 can be used as the polishing particles, andin order to decrease difference in height between the top surface of theluminous pillars and the top surface of the gap filling material afterfinishing the planarization process, finer particles are moreadvantageous.

In order to conserve the shape of the luminous pillars 10 without anydamage as shown in FIG. 2D, it is preferable that a hard polishing padsuch as a glass is used and force applied to a sample is small. Further,when the CMP process is carried out with applying a large force to thesample and using a soft polishing pad, the uppermost layer of the GaNlayer (the top surface of the p-type GaN layer) can be processed into alens shape 11 a as shown in FIG. 3. This is another advantage of the CMPprocess, and the lens shape 11 a shown in FIG. 3 enhances the luminousefficiency and the straightness of light.

Next, as shown in FIG. 2E, in a final process after the CMP process, thetransparent electrode 6 is formed. That is, the transparent electrode 6is formed in a large area on the p-type GaN which is the top surface ofthe luminous pillars 10 exposed after finishing the planarizationprocess, thereby forming a structure in which the respective luminouspillars are electrically pumped and all the pillars 10 are driven at thesame time. As a material of the transparent electrode 6, a thin Ni/Au orITO is used. Then, the p-type electrode 7 ad the n-type electrode 8 isformed and then the resultant structure is heated.

On the other hand, by varying the process variables in theaforementioned ICP etching process, the slope of the side surfaces canbe controlled. In general, an etching process without an oblique slopeand with an excellent verticality can be preferred, but it may benecessary to form an oblique side surface, depending upon the selectionof gap filing material. That is, when the DBR material is selected asthe gap filling material, the oblique side surface is more advantageousthan the vertical side surface from the point of view of process. Forexample, by forming the side surfaces of the luminous pillars 10obliquely and filling the gaps therebetween with the gap fillingmaterial of DBR material, the shape shown in FIG. 4 can be obtained. Inother words, the DBR layer 9 a is first formed in the internal sidesurfaces 10 a and the bottom portion of the gaps 12 using ZrO₂/SiO₂ orHfO₂/SiO₂, and then the gap filling material comprising other materialcan be further filled therein. Then, although not shown in FIG. 4, thetransparent electrode 6, the p-type electrode 7 and the n-type electrode8 can be formed as described above.

Furthermore, in the present invention, when the luminous element is usedto have a flip-chip structure in which the substrate 1 of thesemiconductor element is directed upward, a metal electrode 6 a whichallows the flip-chip mounting may be deposited in place of thetransparent electrode.

Although the example described above has a structure in which light isemitted toward a top of element, the present invention is not limited tosuch structure, but may include a flip-chip structure in which light isemitted toward the substrate. In other words, by manufacturing theelement in which the transparent electrode 6 or the metal electrode 6 ais provided into the flip-chip structure as shown in FIG. 5, the lightemitted toward the substrate 1 can be used with a high efficiency.

Furthermore, the flip-chip structure prevent a local discontinuity ofthe thin transparent electrode which may be generated due to a finedifference in height of the top surface of the gap filling material (thebottom surface of the gap filling material in FIG. 5) and the luminouspillars 10. That is, the luminous pillars are prevent from not beingdriven at the same time due to the local discontinuity.

Like this, when the present invention employs the flip-chip structure,the aforementioned problems can be completely solved, thereby obtaininga high light efficiency. In addition, considering that the luminousefficiency is increased with smaller difference of refraction indexbetween the luminous layer and its adjacent medium, the emitted lightnecessarily passes through the substrate in the flip-chip structure, andthus it is possible to obtain a higher luminous efficiency compared witha structure in which the emitted light is directly discharged in air.

Furthermore, in addition to the final element structure of theaforementioned examples of the present invention, an AR(Anti-reflection) layer may be coated, or the DBR layers may bedeposited on the top and bottom surfaces of the element, thereby obtainan RCLED (Resonant Cavity LED) structure. In this case, even if thereflectivity thereof is not as high as the DBR layer formed in the VCSEL(Vertical Cavity surface emitting diode), the DBR layer having a properreflectivity can enhance re-cyclability of the emitted light and thus iseffective for improving quality of the emitted light.

Second Embodiment

FIGS. 6A to 6D are views illustrating a method of manufacturing themicro LED using a selective re-growth method in place of a dry etchingmethod in manufacturing the micro LED in the first embodiment.

The second embodiment employs a selective re-growth method, unlike thefirst embodiment employing the dry etching method for formation of theluminous pillars 10. In this case, the second embodiment does notrequire the CMP process.

As shown in FIG. 6A, first, a GaN buffer layer 2 a for re-growing theluminous pillars 10 (see FIG. 6D) is grown on the substrate 1, and thenthe oxide film 5 is deposited thereon in a thickness of the luminouspillars desired to obtain. By patterning the oxide film 5 using a wetetching method, the shape shown in Fig. B is obtained, and the re-growthis carried out using the exposed GaN buffer layer 2 a (see FIG. 6C). Asthe re-grown layer, the n-type GaN layer 2, the InGaN/GaN QW activelayer 3 and the p-type GaN layer 4 are grown on the n-type GaN bufferlayer 2 a (see FIG. 6D). As shown in FIG. 6D, it is preferable that thethickness of the re-grown layer constituting the luminous pillars 10 isequal to that of the oxide film. Although not shown in the drawings, thetransparent, the p-type electrode and the n-type electrode are finallyformed as in the first embodiment, to complete the element.

Of course, in this embodiment, a pair of DBR layers may be formed on thesubstrate and the uppermost layer of the completed element to form aresonant cavity LED, or the substrate and the uppermost layer may becoated with the AR layer to further enhance the light efficiency.

Although the micro-sized nitride semiconductor LED is described in theabove embodiments, the present invention may easily apply to all typesof micro-sized light emitting diodes.

1. A nitride micro LED (Light Emitting Diode) with high brightness,comprising: a plurality of micro-sized luminous pillars having an n-typeGaN layer formed on a substrate, and active layer 3 formed on the n-typeGaN layer, and a p-type GaN layer formed on the active layer; a gapfilling material filled between the luminous pillars to havesubstantially the same height as the luminous pillars, wherein the gapfilling material includes at least one selected from SiO₂, Si₃N₄, or acombination thereof, polyamide, and ZrO₂/SiO₂ or HfO₂/SiO₂, and whereinthe gap filling material is formed to have substantially the same heightas the luminous pillars through a CMP (Chemical Mechanical Polishing)process; a p-type transparent electrode formed on a top surface of thegap filling material and the luminous pillars; a p-type electrode formedon the p-type transparent electrode; an n-type electrode electricallyconnected to the n-type GaN layer, wherein an array of the luminouspillars is driven at the same time; and wherein a top surface of thep-type GaN layer of the luminous pillars has convex surfaces formedthrough the CMP process.
 2. A nitride micro LED (Light Emitting Diode)with high brightness, comprising: a plurality of micro-sized luminouspillars having an n-type GaN layer formed on a substrate, and activelayer 3 formed on the n-type GaN layer, and a p-type GaN layer formed onthe active layer; a gap filling material filled between the luminouspillars to have substantially the same height as the luminous pillars; ap-type transparent electrode formed on a top surface of the gap fillingmaterial and the luminous pillars; a pair of DBR (Distributed BraggReflectors) layers formed on a top surface of the transparent electrodeand a bottom surface of the substrate, respectively; a p-type electrodeformed on the p-type transparent electrode; and an n-type electrodeelectrically connected to the n-type GaN layer, wherein an array of theluminous pillars is driven at the same time.
 3. A nitride micro LED(Light Emitting Diode) with high brightness, comprising: a plurality ofmicro-sized luminous pillars having an n-type GaN layer formed on asubstrate, and active layer formed on the n-type GaN layer, and a p-typeGaN layer formed on the active layer, wherein the luminous pillars haveside surfaces that are formed obliquely; a gap filling material filledbetween the luminous pillars to have substantially the same height asthe luminous pillars; a DBR layer made of ZrO₂/SiO₂ or HfO₂/SiO₂ andformed below the gap filling material within gaps between the luminouspillars; a p-type transparent electrode formed on a top surface of thegap filling material and the luminous pillars; a p-type electrode formedon the p-type transparent electrode; an n-type electrode electricallyconnected to the n-type GaN layer, wherein an array of the luminouspillars is driven at the same time.